Why do blue Jays and snakes have hemoglobin in their blood?

Blue jays and snakes, like all vertebrates, have hemoglobin in their blood to efficiently transport oxygen from the lungs to the body's tissues and facilitate the removal of carbon dioxide. Hemoglobin binds to oxygen in the lungs, allowing it to be delivered to cells for metabolism. In reptiles like snakes, hemoglobin also plays a crucial role in adapting to varying oxygen levels in their often low-oxygen environments. Overall, hemoglobin is essential for maintaining cellular respiration and overall metabolic functions in these animals.